I. Field of Invention
The present invention relates to devices which control the amount of air available to a diesel engine.
II. Description of the Prior Art
It is well known that the speed of a diesel engine, that is the number of revolutions per minute, can be controlled by adjusting the amount of fuel injected into that engine and adjusting the timing of that fuel injection. However, if some control over the amount of air entering into the air suction passage of such a diesel engine is not maintained, the diesel engine is subject to violent vibrations and objectionable noises due to the existence of an excess amount of sucked air. Such vibration and noise is especially prevalent when a diesel engine is idling or operating under low load conditions. Such vibrations and noise are uncomfortable to the driver and passengers.
Prior art devices are known which employ a throttle valve to control the volume of air flow in an air suction passage of an engine. Such prior art throttle valves operate so as to restrict the flow of air through the air suction passage when the engine is in a low load condition. Throttle valve arrangements are known which employ a passage external to the air suction passage to by-pass the throttle valve. The amount of air flow through such a external passage is controlled by an air flow controlling means. However, the construction of an effective external passage has in the past been complex and, therefore, expensive.
It is, accordingly, an object of the present invention to provide a new and improved air suction device for a diesel engine which reduces vibration and noise due to excessive amounts of air flowing through the air suction passage of the engine.
It is another object of the present invention to provide a new and novel air suction device for a diesel engine which selectively restricts air flow through an air suction passage but yet is simple and inexpensive to construct.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.